A high-end Long Island caterer has been accused of committing a major sin by using the same kitchen and utensils to prepare kosher and nonkosher foods.

But the owner of Morrell Caterers yesterday denied the claims made in a lawsuit by the general manager and chef at the 57-year-old company, which has locations in Melville, Lawrence and Woodbury.

“I have never violated any rules,” Scott Morrell said.

“This is a very calculated and cynical deliberate way of destroying my company.”

Chef Michael Savitsky and general manager Tom Cataldo, who both crashed Morrell’s press conference, have filed a suit claiming the owner cut kosher corners by using the same equipment to prepare nonkosher items, such as shrimp and lobster, as he did to cook kosher.